The use of consumer electronic devices is pervasive throughout modern society. Consumer electronic devices are used to perform many varied functions. Some functions performed by the consumer electronic devices are practical necessities of modem life. And, ready access to, and use of, devices capable of performing such functions is needed.
The electronic devices are formed of electronic circuits that are of any of various constructions, e.g., formed of discrete or integrated circuits. Different circuits exhibit different load characteristics, sometimes identified by their resistive load characteristics. The load characteristics of a device are determinative, in part, of the power requirements required to power the device. While electronic circuitries require direct current power for their operation, the characteristics of the direct current power are device-dependent. And, as a result, different levels of operative power are needed by different devices for their operation.
Power grids forming power infrastructures have been extensively deployed to provide populated areas with electrical power, available for use, inter alia, to power consumer electronic devices. In North America, for instance, power grids provide alternating current power, available at 110 volt levels. Power derived from a power grid permits powering of electronic devices. When the circuitries of the electronic devices are, as noted above, constructed to be operable with direct-current energy, power sourced at the power grid must be converted into a form useable by the electronic devices. When the power grid-sourced energy is of alternating current characteristics, the energy must be converted into direct current energy.
A power converter is used to convert the power grid-sourced energy into energy of characteristics suitable for powering the electronic device. Typically, the circuitry of the electronic device operates at relatively low voltage levels while the grid-sourced energy is of relatively high voltage levels. The power converter both converts the alternating current energy into direct current energy and also down-converts the input energy to a level useable by the electronic device.
Sometimes, the energy source of operative power used to power an electronic device is sourced at a source of direct current energy, e.g., an automotive battery power supply. A power converter is sometimes also required to convert the energy of the direct current power supply into energy of characteristics appropriate to power the electronic device. The power converter operates in manners analogous to those just-described with respect to a grid-sourced power supply to convert the supplied power into energy of characteristics appropriate to power the electronic device.
Some conventional power converters operate only to convert alternating current energy of a selected level into direct current energy. Other conventional power converters operate only to convert direct current energy into direct current energy of other characteristics. And, some power converters are capable of converting both direct current energy and alternating current energy into direct current output energy of characteristics capable of powering a load device.
Power conversion of energy from an input form into an output form is not one hundred percent efficient. That is to say, not all of the input energy is converted into useful output energy. Part of the input energy is, instead, converted into thermal energy, i.e., heat energy. Generation of the heat energy is disadvantageous, not only for the reason that greater amounts of input energy are required so that the output energy is of appropriate power levels, but also for the reason that the heat energy increases the temperature of the components of the power converter, increasing the rate at which the components of the converter fail. The component failure rate is sometimes quantified as a mean-time-between-failure rate.
Some conventional power converters include multiple power conversion stages, each of which exhibits a less than one hundred percent efficiency. When the stages are connected in a cascaded configuration, the reduction in the efficiency of the power converter is compounded. That is, if two different power converter stages are positioned in series, efficiency reductions occur at each of the stages, and the resultant output power is of a twice-reduced level. For instance, if each stage, positioned, in cascade, exhibits an eighty-five percent efficiency, the output at the second stage is seventy-three percent of the input energy. Twenty-seven percent of the input energy is not used, and, instead, is converted into thermal energy. As the thermal energy is dissipated through the elements of the power converter, the temperature levels of the elements of the power converter increase, and the mean-time-between-failure rate of the elements correspondingly increase.
An improved power converter exhibiting improved efficiency is therefore needed.
It is in light of this background information related to power conversion of electrical power energy that the significant improvements of the present invention have evolved.